Enhanced Surface Reaction Kinetics and Charge Separation of p鈥搉 Heterojunction Co3O4/BiVO4 Photoanodes

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• 作者：Xiaoxia Chang ; Tuo Wang ; Peng Zhang ; Jijie Zhang ; Ang Li ; Jinlong Gong
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：July 8, 2015
• 年：2015
• 卷：137
• 期：26
• 页码：8356-8359
• 全文大小：324K
• ISSN：1520-5126

文摘

Surface reaction kinetics and bulk charge separation are both critical to the efficiency of solar water splitting. In addition to the well-documented surface catalytic effect, the promotion of bulk charge separation upon loading of cocatalysts has rarely been reported. This paper describes the synergetic enhancement of surface reaction kinetics and bulk charge separation by introducing discrete nanoisland p-type Co₃O₄ cocatalysts onto n-type BiVO₄, forming a p鈥搉 Co₃O₄/BiVO₄ heterojunction with an internal electric field to facilitate charge transport. Being highly dispersed on the surface of photoanodes, the nanoisland cocatalysts could suppress the formation of recombination centers at the photoanode/cocatalyst interface. This cocatalyst-loading method achieved a charge separation efficiency of up to 77% in the bulk and 47% on the surface of catalysts. An AM 1.5G photocurrent of 2.71 mA/cm² at 1.23 V versus the reversible hydrogen electrode for water oxidation was obtained, which is the highest photocurrent yet reported for Co-catalyzed undoped BiVO₄ photoanodes, with a photoconversion efficiency of 0.659%.